1. Field of the Invention
This invention relates to novel steroid derivatives, processes for preparing such steroid derivatives, and pharmaceutical compositions for curing or alleviating inflammation or rheumatism comprising the same as an active component.
2. Description of the Background Arts
Many steroid derivatives are known to possess anti-inflammatory activity. They are used for the most part as drugs for external application for the treatment of chronic rheumatism and dermatosis. In recent years, steroid derivatives possessing stronger local anti-inflammatory activity, such as dexamethasone valerate, dexamethasone dipropionate, clobetasol propionate, and the like, have been developed.
These steroid derivatives, however, exert, through percutaneous absorption, systemic action along with the strong local anti-inflammatory activity. Furthermore, there is concern about side effects which may be caused by such systemic action.
Development of steroid derivatives having strong anti-inflammatory action with a high local selectivity and no side effects have therefore been desired.
In view of this situation, the present inventors have synthesized a number of ester derivatives of dexamethasone in which the 17- or 21-position --OH is esterified, and have investigated their pharmaceutical effects. As a result, the inventors have found that steroid derivatives of formula (I) below exhibited strong local anti-inflammatory action with the least systemic action, and were useful for the treatment not only of inflammation but also of rheumatism. Such a finding has led to the completion of the present invention.